The cost of housebuilding and investment in big construction projects in Britain has been inflated by millions of pounds by the collusion of the three large foreign-owned cement manufacturers that dominate the industry.

After a two-year investigation, the Competition Commission has ordered two of the groups, Lafarge Tarmac and Hanson, to dispose of facilities to create a new, independent rival.

Its report, however, appears to have set it on course for a confrontation with the companies, neither of which has ruled out taking its grievances to the Competition Appeals Tribunal.

Lafarge Tarmac accused the Competition Commission’s findings as being unreasonable